Aboveground biomass stock of native woodland on a Brazilian sandy coastal plain: Estimates based on the dominant tree species

Abstract: The restingas of coastal Brazil are vegetation mosaics that include forests and open woodlands. One of the most common restinga vegetation types in Rio de Janeiro state, an open woodland, is dominated by the crassulacean acid metabolism (CAM) tree Clusiahilariana Schltdl. (Clusiaceae). We provide allometric equations and biomass estimation for this species on three sites varying woody plant cover. Estimated aboveground biomass stock of C. hilariana plus the litter accumulated underneath the canopy of these plants ranged from 0.64 to 8.63 t ha−1 depending on plant cover. These values are often comparable to those of the entire woody component of many neotropical savannas, which have been claimed to have important impact on global carbon cycles. The litter-layer represents 31% of aboveground biomass, which is very high when compared to other tropical savannas. This indicates that slow decomposition may play an important role on carbon accumulation at the studied ecosystem. Thus, C. hilariana, despite its conservative strategy of carbon acquisition via CAM, gives a high contribution to biomass stock in this nutrient-poor coastal vegetation in the tropics.

Greenhouse gas fluxes from drained organic forestland in Sweden

von Arnold, K. - Hanell, B. - Stendahl, J. - Klemedtsson, L. (2005)

Scandinavian Journal of Forest Research 20: 400 - 411

Abstract: The objective of this study was to estimate the contribution of drained organic forestlands in Sweden to the national greenhouse gas budget. Drained organic forestland in Sweden collectively comprises an estimated net sink for greenhouse gases of - 5.0 Mt carbon dioxide (CO2) equivalents year - 1 (range - 12.0 to 1.2) when default emission factors provided by the Good practice guidance for land use, land-use change and forestry are used, and an estimated net source of 0.8 Mt CO2 equivalents year - 1 (range - 6.7 to 5.1) when available emission data for the climatic zones spanned by Sweden are used. This discrepancy is mainly due to differences in the emission factors for heterotrophic respiration. The main uncertainties in the estimates are related to carbon changes in the litter pool and releases of soil CO2 and nitrous oxide.

Abstract: The large global extensions of arid and semi-arid regions together with their widespread degradation give these areas a high potential to sequester carbon. We explored the possibilities of semi-arid ecosystems to sequester carbon by means of rangeland exclusion and afforestation with Pinus ponderosa in NW Patagonia (Argentina). We sampled all pools where organic carbon accumulates in a network of five trios of adjacent grazed, non-grazed and afforested stands (age: 12–25 years, density 605–1052 trees ha−1). After 15 years since trees were planted, afforestation added ~50% more C to the initial ecosystem carbon pool, with annual sequestration rate ranging 0.5–3.3 Mg C ha−1 year−1. Carbon gains in afforested stands were higher above than below-ground (150% vs. 32%). Root biomass differences (374% more in afforested vs. grazed stands, p=0.0011) explained below-ground carbon contrasts whereas soil organic carbon showed no differences with afforestation. By contrast, grazing exclosures did not result in significant changes in the total carbon storage in comparison with the adjacent grazed stands ( p=0.42) suggesting a slow ecosystem recovery in the time frame of this study (aprox. 15 years of exclusion). Nevertheless, higher litter amount was found in the former (+53%, p=0.07). Neither, soil organic carbon nor root carbon showed significant differences between grazed and non-grazed conditions. Considering that more than 1.1 millions of hectares of the studied ecosystems are highly degraded and suitable for tree planting, afforesting this area could result in a carbon sequestration rate of 1.7 Tg C year−1, almost 6% of the current fossil fuel emissions of Argentina; however environmental consequences which could emerge from this deep land use shift must be taken into account when afforestation program are being designed.

Recent trends in vegetation dynamics in the African Sahel and their relationship to climate

Herrmann, S.M. - Anyamba, A. - Tucker, C.J. (2005)

Global Environmental Change Part A 15 (4): 394-404

Abstract: Contrary to assertions of widespread irreversible desertification in the African Sahel, a recent increase in seasonal greenness over large areas of the Sahel has been observed, which has been interpreted as a recovery from the great Sahelian droughts. This research investigates temporal and spatial patterns of vegetation greenness and rainfall variability in the African Sahel and their interrelationships based on analyses of Normalized Difference Vegetation Index (NDVI) time series for the period 1982–2003 and gridded satellite rainfall estimates. While rainfall emerges as the dominant causative factor for the increase in vegetation greenness, there is evidence of another causative factor, hypothetically a human-induced change superimposed on the climate trend.

Abstract: During recent years harvested wood products (HWP) have received growing attention because they may be included in national greenhouse gas (GHG) inventories and possibly Kyoto Protocol (KP) accounting procedures in future commitment periods, with practical and economic consequences for both reporting and timber markets. The Intergovernmental Panel on Climate Change (IPCC) has identified three approaches to estimating and reporting carbon (C) stock in HWP; the stock-change approach, the production approach, and the atmospheric-flow approach. Should countries choose to report C stocks in HWP, one approach needs to be universally agreed for consistency. Using a model, the C stock both in use and in solid waste disposal sites (SWDS) at a national scale in Ireland was estimated and compared for the period 1961–2003 with uncertainty in the estimates generated using a Monte Carlo analysis. In 2003, the stock-change approach yielded the highest C sink, relative to the IPCC default approach of 375 Gg C yr−1±40% with the production approach and atmospheric-flow approach estimating the stock change at 271 Gg C yr−1±48% and 149 Gg C yr−1±31%, respectively. On the basis of the model results, the implications of selecting one approach over another and the contribution HWP may have in the future to help Ireland reach its reduction target under the KP are discussed.

Carbon fluxes from a tropical peat swamp forest floor

Abstract: A tropical ombrotrophic peatland ecosystem is one of the largest terrestrial carbon stores. Flux rates of carbon dioxide (CO2) and methane (CH4) were studied at various peat water table depths in a mixed-type peat swamp forest floor in Central Kalimantan, Indonesia. Temporary gas fluxes on microtopographically differing hummock and hollow peat surfaces were combined with peat water table data to produce annual cumulative flux estimates. Hummocks formed mainly from living and dead tree roots and decaying debris maintained a relatively steady CO2 emission rate regardless of the water table position in peat. In nearly vegetation-free hollows, CO2 emission rates were progressively smaller as the water table rose towards the peat surface. Methane emissions from the peat surface remained small and were detected only in water-saturated peat. By applying long-term peat water table data, annual gas emissions from the peat swamp forest floor were estimated to be 3493±316 g CO2 m-2 and less than 1.36±0.57 g CH4 m-2. On the basis of the carbon emitted, CO2 is clearly a more important greenhouse gas than CH4. CO2 emissions from peat are the highest during the dry season, when the oxic peat layer is at its thickest because of water table lowering.

Effects of afforestation on water yield: a global synthesis with implications for policy

Farley, K.A. - Jobbagy, E.G. - Jackson, R.B. (2005)

Global Change Biology 11: 1565–1576

Abstract: Carbon sequestration programs, including afforestation and reforestation, are gaining attention globally and will alter many ecosystem processes, including water yield. Some previous analyses have addressed deforestation and water yield, while the effects of

afforestation on water yield have been considered for some regions. To assess and predict these effects globally, we analyzed 26 catchment data sets with 504 observations, including annual runoff and low flow. We examined changes in the context of several variables, including original vegetation type, plantation species, plantation age, and mean annual precipitation (MAP). All of these variables should be useful for understanding and modeling the effects of afforestation on water yield. We found that annual runoff was reduced on average by 44% (- 3%) and 31% (- 2%) when grasslands and shrublands were afforested, respectively. Eucalypts had a larger impact than other tree species in afforested grasslands (P50.002), reducing runoff (90) by 75% (- 10%), compared with a 40% (- 3%) average decrease with pines. Runoff losses increased significantly with plantation age for at least 20 years after planting, whether expressed as absolute changes (mm) or as a proportion of predicted runoff (%) (Po0.001). For grasslands, absolute reductions in annual runoff were greatest at wetter sites, but proportional reductions were significantly larger in drier sites (Po0.01 and Po0.001, respectively). Afforestation effects on low flow were similar to those on total annual flow, but proportional reductions were even larger for low flow (Po0.001). These results clearly demonstrate that reductions in runoff can be expected following afforestation of grasslands and shrublands and may be most severe in drier regions. Our results suggest that, in a region where natural runoff is less than 10% of MAP, afforestation should result in a complete loss of runoff; where natural runoff is 30% of precipitation, it will likely be cut by half or more when trees are planted. The possibility that afforestation could cause or intensify water shortages in many locations is a tradeoff that should be explicitly addressed in carbon sequestration programs.

Biomass carbon accumulation by Japan's forests from 1947 to 1995

Fang, J. - Oikawa, T. - Kato, T. - Mo, W. - Wang, Z. (2005)

Global Biogeochemical Cycles 19 (2)

Abstract: Forest ecosystems in the Northern Hemisphere function as carbon (C) sinks for atmospheric carbon dioxide; however, the magnitude, location, and cause of the sinks remain uncertain. A number of field measurements of forest biomass and systematic national forest inventories in Japan make it possible to quantify the C sinks and their distribution. Allometric relationships between forest biomass and stem volume were obtained for the major forest types in Japan from 945 sets of direct field measurements across the country. These relationships were used to estimate the changes in C accumulations of aboveground biomass and total living biomass from 1947 to 1995 from the national forest inventories of 1947, 1956, 1961, 1965, 1975, 1980, 1985, 1990, and 1995. The results showed that the C accumulations have significantly increased during the last 50 years. The C density (C stock per hectare) and total C stock of aboveground biomass increased from 27.6 Mg C/ha and 611.7 Tg C in 1947 to 43.2 Mg C/ha and 1027.7 Tg C in 1995, respectively, and those of total living biomass increased from 33.9 Mg C/ha and 751.8 Tg C in 1947 to 53.6 Mg C/ha and 1274.8 Tg C in 1995. These increases were remarkable during 1976–1995, with a net increase of 5.6 Mg C/ha and 369 Tg C for the C density and total living biomass. These results suggest that Japan's forest vegetation is a significant C sink. In the past 20 years, living vegetation has sequestered 18.5 Tg C annually, 14.6 Tg C of which was accumulated in aboveground biomass. The total C sink for the whole forest sector (including nonliving biomass) of Japan was estimated as 36 Tg C/yr if using the net change ratio of nonliving biomass C to living biomass C derived from the United States and Europe. On the basis of average C sink per hectare, Japan's forests have a higher sequestration rate (0.77 Mg C ha−1 yr−1) than the average of the other northern countries (0.14–0.19 Mg C ha−1 yr−1). The expansion and regrowth of planted forests are two major causes for this increased C uptake; planted forests contribute ∼80% of the total C sink in Japan. The suitable oceanic climate for fast forest growth and effective forest management practice may be the principal factors for such a large sink.

Tree allometry and improved estimation of carbon stocks and balance in tropical forests

Abstract: Tropical forests hold large stores of carbon, yet uncertainty remains regarding their quantitative contribution to the global carbon cycle. One approach to quantifying carbon biomass stores consists in inferring changes from long-term forest inventory plots. Regression models are used to convert inventory data into an estimate of aboveground biomass (AGB). We provide a critical reassessment of the quality and the robustness of these models across tropical forest types, using a large dataset of 2,410 trees ≥ 5 cm diameter, directly harvested in 27 study sites across the tropics. Proportional relationships between aboveground biomass and the product of wood density, trunk cross-sectional area, and total height are constructed. We also develop a regression model involving wood density and stem diameter only. Our models were tested for secondary and old-growth forests, for dry, moist and wet forests, for lowland and montane forests, and for mangrove forests. The most important predictors of AGB of a tree were, in decreasing order of importance, its trunk diameter, wood specific gravity, total height, and forest type (dry, moist, or wet). Overestimates prevailed, giving a bias of 0.5–6.5% when errors were averaged across all stands. Our regression models can be used reliably to predict aboveground tree biomass across a broad range of tropical forests. Because they are based on an unprecedented dataset, these models should improve the quality of tropical biomass estimates, and bring consensus about the contribution of the tropical forest biome and tropical deforestation to the global carbon cycle.

The net carbon flux due to deforestation and forest re-growth in the Brazilian Amazon: analysis using a process-based model

Abstract: We developed a process-based model of forest growth, carbon cycling and land-cover dynamics named CARLUC (for CARbon and Land-Use Change) to estimate the size of terrestrial carbon pools in terra firme (non-flooded) forests across the Brazilian Legal Amazon and the net flux of carbon resulting from forest disturbance and forest recovery from disturbance. Our goal in building the model was to construct a relatively simple ecosystem model that would respond to soil and climatic heterogeneity that allows us to study the impact of Amazonian deforestation, selective logging and accidental fire on the global carbon cycle. This paper focuses on the net flux caused by deforestation and forest re-growth over the period from 1970 to 1998. We calculate that the net flux to the atmosphere during this period reached a maximum of 0.35 PgC yr1 (1 PgC= 1 × 1015 gC) in 1990, with a cumulative release of 7 PgC from 1970 to 1998. The net flux is higher than predicted by an earlier study (Houghton et al., 2000) by a total of 1 PgC over the period 1989–1998 mainly because CARLUC predicts relatively high mature forest carbon storage compared with the datasets used in the earlier study. Incorporating the dynamics of litter and soil carbon pools into the model increases the cumulative net flux by1 PgC from 1970 to 1998, while different assumptions about land-cover dynamics only caused small changes. The uncertainty of the net flux, calculated with a Monte-Carlo approach, is roughly 35% of the mean value (1 SD).

Trading Water for Carbon with Biological Carbon Sequestration

Abstract: Carbon sequestration strategies highlight tree plantations without considering their full environmental consequences. We combined field research, synthesis of more than 600 observations, and climate and economic modeling to document substantial losses in stream flow, and increased soil salinization and acidification, with afforestation. Plantations decreased stream flow by 227 millimetres per year globally (52%), with 13% of streams drying completely for at least 1 year. Regional modeling of U.S. plantation scenarios suggests that climate feedbacks are unlikely to offset such water losses and could exacerbate them. Plantations can help control groundwater recharge and upwelling but reduce stream flow and salinize and acidify some soils.

Estimation of the biomass stock of trees in Sweden: comparison of biomass equations and age-dependent biomass expansion factors

Abstract: Differences and uncertainties of alternative methods applicable to estimation of biomass in national greenhouse gas inventories are evaluated. The alternative methods employed to obtain biomass estimates of trees are (1) aggregated stand-level volume estimates multiplied by biomass expansion factors (BEF), and (2) biomass equations applied to tree-wise data of a national forest inventory. In comparison to the reference value obtained using tree-wise biomass equations, the age-dependent BEFs for the whole of Sweden resulted in a 6.7% lower aboveground biomass estimate. The estimates were the closest for conifer-dominated forests in central Sweden, and the largest discrepancies were for spruce in southern Sweden. This result indicates that these age-dependent BEFs cannot be applied to conditions where stand development deviates from the conditions under which the BEFs were developed. The degree of uncertainty in both methods was highest in the young age-classes. At the regional level, the relative standard errors of the BEF-based biomass estimates were in the range of 4–13%.

2) Forest and Climate Change News

As part of the Trees for Global Benefits Project, 156 farmers in Bushenyi, Uganda have planted about 15,000 trees. They are part of the global system of carbon trade and credits. According to the Kyoto Protocol, one carbon credit is one metric tonne of carbon dioxide emitted from the burning of fossil fuels such as oil or coal. The credits have been purchased by a major international company that produces drink and food packaging, a total sale of 11,200 carbon credits at $3.83 a tonne. This carbon money translates to $36,666, dispersed among the farmers according to the number of trees he has planted.

(Note from the editors: This transaction does not imply that tCERs / lCERs have been issued by now)

Government will explore alternative measures to address deforestation liabilities

New Zealand Government will explore alternative measures to address deforestation liabilities. Officials have been asked to explore alternative measures to address the issue of greenhouse gas emissions arising from deforestation, as part of the government’s review of climate change policies.

Rising temperatures and a decline in the amount of snow in the Rocky Mountains have slowed the release of carbon dioxide, the main gas blamed for global warming, from forest soil, researchers said on Wednesday. Professor Russell Monson, who headed the research team, described it as a "serendipitous effect" which could have important ramifications on how much CO2 is emitted from forests.

Climate change 'brings fire danger'

Climate change will cause more bushfires in southeast Australia over coming decades, a new study has found. The CSIRO research found the number of high risk fire days could increase by up to 60 per cent by 2050. The study assessed fire weather risk using daily temperature, rain, humidity, and wind data over the past 30 years at 17 forest and grassland sites around southeast Australia.

3) Forest and Climate Change Info & Events

Report of CDM Afforestation and Reforestation Working Group

UNFCCC Headquarters, Bonn, Germany

7-8 February, 2006

The report of the seventh meeting of the CDM Afforestation and Reforestation Working Group (A/R WG) and its annexes are available in the AR WG section of UNFCCC CDM web site. Among other issues, 8 proposed new methodologies for afforestation and reforestation under the CDM were considered, of which three were recommended for consideration by the CDM EB.

Proposed new Afforestation & Reforestation methodologies

Two proposals on new Afforestation/Reforestation baseline and monitoring methodologies have been submitted to the CDM Executive Board for its review and were available for public input from 16 February - 08 March 2006.

ARNM0019: Reforestation around Pico Bonito National Park, Honduras

ARNM0020: Afforestation for Combating Desertification in Aohan County, Northern China

Report of the 23rd meeting of the CDM Executive Board

The report of the twenty-third meeting of the CDM Executive Board (22 - 24 February 2006), including its annexes, is available on the UNFCCC CDM web site. Among others, the annexes contain the revised CDM-AR Project Design Document and respective guidelines, the revised guidelines for CDM-AR baseline and monitoring methodologies, the Project Design Document for Small Scale AR CDM, the definition of renewable biomass as well as guidance of national and/or sectoral policies and circumstances particular to A/R project activities.

Call for public input on draft Joint Implementation Project Design Document form and draft guidelines for users

Background: At its first meeting, the JI supervisor committee agreed on a draft joint implementation project design document (JI PDD) form. At its second meeting, it agreed on draft guidelines for users of the JI PDD form and requested the secretariat to launch a call for public input on the structure and content of the JI PDD form and the respective draft guidelines as well as on the need for development of a separate JI PDD form for LULUCF projects.

Background: COP-11 initiated a 2-year process to consider approaches to stimulate action for reducing emissions from deforestation in developing countries. The objective of our workshop is to provide a timely forum for an informal discussion and assessment of methodological and policy approaches for reducing emissions from deforestation. The workshop will base its discussions on the published literature, the 31 March submissions by governments and observer organizations, and inputs by workshop participants. Anticipated outputs include a side-event at SBSTA 24 to present major findings of our workshop, including initial ideas for the SBSTA workshop terms of reference.

Relevant Literature and Web Links: If available, please send any literature or web links that are relevant to the workshop topic and that you would like to share with other participants. These will be added to the workshop website.

Submissions by parties and observer organizations

Submissions by parties and observer organizations to the UNFCCC Secretariat containing views on issues relating to reducing emissions from deforestation in developing countries were due on March 31st, 2006. They will be published shortly online at: http://unfccc.int/2860.php .

The Forest Resource Assessment 2005 examines current status and recent trends for about 40 variables, covering the extent, condition, uses and values of forests and other wooded land, with the aim of assessing all benefits from forest resources. It contains data and analysis of global carbon stock (biomass, dead wood, litter and soil) and trends between 1990 and 2005. FRA 2005 estimates that the world’s forests store 283 Gigatonnes (Gt) of carbon in their biomass alone, and that the carbon stored in forest biomass, deadwood, litter and soil together is roughly 50 percent more than the amount of carbon in the atmosphere. Carbon in forest biomass decreased in Africa, Asia and South America in the period 1990-2005, but increased in all other regions. For the world as a whole, carbon stocks in forest biomass decreased by 1.1 Gt of carbon annually, owing to continued deforestation and forest degradation partly offset by forest expansion (including planting) and an increase in growing stock per hectare in some regions.

Tree plantations still valid as carbon sinks

Commentary by Phil Polglase, Keryn Paul and Trevor Booth

ENSIS (2006)

Description: An article published in the international science journal, Nature, by Keppler and colleagues from the Max Planck Institute in Germany reported for the first time that plants can directly emit methane. This finding is highly significant as methane is an important greenhouse gas and was thought to come only from anaerobic (oxygen limited) conditions such as from bogs, wetlands, landfills, rice paddies, and from livestock, termites, and from vegetation fires. Subsequent speculative media reports have been fuelled by an opinion piece by Lowe in the same issue of Nature that states ‘we now have the spectre that new forests might increase greenhouse warming through methane emissions rather than decrease it by sequestering CO2’. We tested this assumption using the methodology provided in Keppler’s article to compare estimates of methane emissions for seven different regional case studies of afforestation in Australia with the amounts of carbon stored to determine the overall effect. We calculated that the average amount of methane emitted would off-set less than 5% of the amount of carbon dioxide stored in terms of its effect in contributing to global warming. However, under afforestation the key question is actually ‘what is the amount of change when planting new forests on agricultural land’? Several issues need to be addressed, for example soils take up and oxidise methane. Also, Keppler suggests that all plants emit methane, so it may even be possible for some agricultural land practices to emit more methane than forests for any given land area. Based on all the available evidence so far, the use of new forests as carbon sinks remains valid. Methane emissions by trees might have a small negating impact, but the effect could be much less or even positive, depending on the net emissions of methane from trees and soil relative to the preceding agricultural land. The article by Keppler has created enormous interest internationally and is sure to lead to much more work in this area. It has important implications for understanding the role of terrestrial vegetation in contributing to the global methane budget.

5) Climate Change jobs

PhD assistantship with the Centre for Ecosystem Studies

As part of the EU-EFORWOOD project, the Forest Ecosystems team of Alterra develops a methodology for scenario analysis of forest dynamics and timber resource availability in Europe. Inputs are different scenarios of forest management, and changing environmental conditions associated with climate change. The PhD project will focus on the development of a general simulation model for forest growth and forest ecosystem dynamics that will be used, together with forest inventory data, for scenario analysis of forest development and forest use in Europe.

The objective of CLIM-FO-L is to be a forum for sharing current information and experiences about climate change and forestry amongst experts and non-experts. CLIM-FO-L will send periodically to subscribers synopsis of contributions, indicating how to obtain more detailed information on the topic. CLIM-FO-L is a service provided by the FAO Forest Resources Division, Forest Conservation Service (FORC).

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